Anyone read any really really good ones?

i really enjoyed "tommyknockers" by stephen king

Does Blindsight count? It has scifi, aliens, vampires, cyborgs and even zombies(some of whom are ALSO vampires AND cyborgs as well!). And it leaves a lot of fridge-horror to think about, and will probably be soon considered a classic like the hyperion series or something.

"The Day of the Triffids" by J. Wyndham (in soviet russia, plants noms you)
"Solaris" and "Invincible" both by S. Lem (scifi with just little horror but are "classics" blabla)
"After the Flood", author ungoogleable due to generic title (post apocalyptic, bit disgusting at times)

The "Dune" series.

This genre is rather rare, mostly because they oppose each other. Fear is basically the != of sience. Somebody doing sience, analyses stuff, developing coutermeasures, thus although something might remain dangerous, real horror, panic or fear never start to creep into hard sci-fi.

Best SciFi books are those, that give you this "Why have i never thought of that?"jolt with there starting idea, and then start unravelling it further and further, and this tickle of amazment never stops.

Deepness in the Sky was one of those. Not horror though.

If you want SciFi Horror, turn on the news, and then your Imagination.

Except, of course, when it's fridge horror, or when guys like Giger show up.

Also, try Lovecraft.

Damn you TVTropes, I have shit to do.